Apparatus for forming materials



NW, 12, 1946. w. B. AHERN Q APPARATUS FOR FORMING MATERIALS Filed Dec.so, 1945 INVENTOR.

Patented Nov. 12, 1946 APPARATUS FOR FORMING MATERIALS William B. Ahern,De Kalb, 111., assignor to The Rudolph Wurlitzer Company, Chicagm'IlL, a

corporation Application December 30, 1943, Serial No. 516,316

This invention relates to an apparatus for moulding plastics, paper,wood, cloth and the like, and particularly that type of material whichmay be moulded and formed with the application of heat and pressure. Itis particularly applicable to forming molded tips to the desired shapeor form under pressure coupled with" heat transfor treatment.

The invention primarily contemplates the application to the material ofa male forming-plug of compressible resilient material such as maycomprise an adherent fluid mass, said plug substantially conforming tothe general shapeof the for-med material, and likewise, to a female formof light sheet heat transfer metal. In the use of such a plug theinvention also contemplates the application of equalized fluid pressureto both the fluid mass of the plug and the thin heat transfer metalform. Such equalized fluid pressure is adapted to sustain the thin metalfemale form andso compress the resilient male form or plug as to causeit to transmit such pressure for compressing the material transverselythereof in different directions. Such a plug may be of soft rubber suchas to be fluid-like in its transmission of pressure while maintainingits adhering mass and shape formation.

The apparatus comprising this invention has the advantage of rapidassembly of the forms within their pressure chambers so as to permit theformed material to be conveniently changed, while at the same timehaving the advantages of rapid heat transfer through a thin sheet femaleform, light in weight and inexpensive, to provide for different sizesand shapes.

The full nature of the invention will be understood from theaccompanying drawing and the following description and claims: I

Fig. 1 illustrates one form and application of the'invention showing theapparatus in central vertical section with parts in elevation.

Fig. 2 illustrates a second or modified-form of the invention showingthe apparatus in central vertical section with portions thereof inelevation.

Referring to Fig. 1, there is illustrated a stationary fixed platenorsupport Ill and-a movable platen or head i l which may be clamped inoperating position and secured by the threadedtie rods and nuts 12. iCarried by the support ['0' there is a cradle l3, open at the top toprovide a pressure chamber ld'and support for the female or contour form15.

4 Claims. (01. 18-19) sufficient inherent strength and rigidity toretain its form and support the material to be formed. It need not be ofsuch thickness and strength as to withstand the pressure to be appliedin the forming operation. Such a contour form has the advantage of beingconveniently and easily formed to the desired contour as well as rapidlytransmitting heat from the chamber M to the material to be formed. Thecontour form I5 is flanged with a peripheral cupped portion indicated atI6'for providing a support therefor in the cradle capable of beingsealed thereabout by the gasket l1. Mounted in sealed position, it 'isremovably secured by the screws l8. Y

The head ll carries a chamber cover l9 coextensive with the cradle l3 towhich a flexible blanket 2| is secured and sealed about its edges by'theclamping ring or members 22. Said blanket is arranged to overlie andpress against a forming plug 20. Said plug comprises an adherent fluidmass such 'as .rubber or similar compressibleresilient material andsubstantially con- Thus said plug serves as a male forming die, but withsufiicient fluidity to transmit pressure in all directions. s

engaging the flange of the contour form. Thus the corrugated surfaceprovides a series of ducts 24 providing atmospheric connection with theinitial space betweengthe plug and work and between the work and form.Thejmaterial to be formed is disposed over or within the contour formand compressed therein by the plug, the material being indicated at 25.

The forming pressure such as to highly compress the material underapplication of heat, is generated in the pressure chamber I4 by steamintroduced'through the steam pipe 26 communieating with the steamdelivery pipe 21 controlled by the steam valve 28 which is incommunication with a water inlet pipe 29 controlled by the valve 30. Thefluid pressure thus created in the chamber is transmitted to thepressure chamber 3] provided between the chamber cover l9 and V theblanket 2i. Thus the pressure exerted on both sides of the thin metalcontour form is equalized so as not to distort it. For this purpose thechamber l4 is'in communication with 32 directly to the chamber 3|. Fordraining the chamber I4 of condensation, there is provided a drain pipe35 communicating with thebottom thereof.

In operation the sheet material 25 to be formed may be placed over orwithin the contour form either preformed or otherwise, whereupon theplug 20 is inserted and the head II lowered. This has the effect ofgenerally conforming the material to the form. When the head has beenpressed down to its operating position as illustrated, it is clamped andtightened so that the blanket rests upon the breather plate 23. Whendesired, the tank 34 will have been filled with the proper liquid. Steamis then admitted to the chamber I4 under pressure, at the same timetransmitting said pressure to the liquid in the tank 34. This equalizedfluid pressure is thereby exerted equally against the plug 20 and thecontour form I5. After the pressure is increased, the resilience orfluidity of the mass in the forming plug causes it .to in turn transmitthe fluid pressure against :the material transversely thereof, wherebysaid material is compressed under high pressure equally throughout itsentire surface and to the contour of the form. At the same time heatcarried by the steam in the chamber I4 is rapidly transmitted throughthe thin metal wall of the form directly to the material. This has theeffect of causing the material 25 to be set in its formed and compressedcondition. Similarly, wherein the material is of such a character as tobe set and formed by cooling, it may be rapidly cooled through the heattransfer of the thin walled form by discharging cooling liquids, such aswater, through the pipe 23. Also, the material first may be heat treatedby the injection of steam into the chamber followed by the injection ofa cooling fluid while maintained in its compressedstate through thepressure transmitted thereby.

In Fig. 2 the contour form I5 is mounted within .an auto-clavecomprising a pressure cylinder II3 for providing a pressure chamber IIA. The form I5 is carried through its outwardly extending flanges upona series of clamps II5 seated upon suitable platforms I I6 mounted uponthe cylinder. The plug is pressed into the form With the material to beformed extending therebetween. The blanket 2| extends over the plug andis clamped about its edges in sealing engagement with the flange of theform by the clamping ring or members I22. Said clamping and sealingaction isprovided by the turn screws carried by the clamps. II5. Asuitable corrugated or apertured breather plate I23 is mounted betweenthe blanket and form to permit entrapped gas to be withdrawn frombetween the plug and form by the vacuum line I24, or otherwise permittedto escape. In fact, the form and plug with the material therein isassembledand the clamps applied outside of the cylinder whereupon theassembled arrangement is mounted on the platforms H6; The assembly alsocarries a water ring I25 wherein it may be desired to protect theblanket 2I from the deleterious effects of steam.

and the cylinder closed, the fluid pressure in the pressure chamber I II may be built up by directing steam therein through the pipe I26 fromthe steam pipe I21 controlled by the valve I28. Water may similarly beadmitted from the water pipe I29 controlled by the valve I38. Thecylinder may be drained by the drain pipe I35.

Theactionis similar to that above described wherein the pressure exertedin the chamber H4 is actually applied about the form and over the plug.When water is placed in the Water ring I25, the steam pressure will betransmitted through such liquid in the manner above described, aswell aswherein the water ring may contain other liquids such as glycerine oroil. Thus the liquid contained in the ring I25 will I protect thematerial and blanket, such as rubber,

from excessive heat during the steam application.

The invention claimed is: 1. Apparatus for forming material involvingthe application of pressure and heat exchange including a female contourform of thin metal for ;rapid heat transmission, means for supportingsaid form within a pressure chamber, a complementary male formcomprising a plug of compressible resilient material, a flexible andresilient blanket associated with and extending over said plug, meanscooperating with said resilient blanket to form a chamber for retaininga pressure transmitting liquid medium thereover for protection thereof,and a source of fluid heat exchange and pressure medium communicatingwith both said pressure chambers for applying equalized pressure on saidliquid medium and female form for compressing said material and causingrapid heat exchange therewith through the thin metal of the female form.

- 2. Apparatus for forming material involving the application ofpressure and heat exchange including a female contour form of thin metalplementary male form comprising a plug of compressible resilientmaterial, a flexible and resilient blanket associated with and extendingover said plug, means cooperating with said resilient blanket to form achamber for retaining a pressure transmitting liquid medium thereoverfor protection thereof, a source of fluid heat exchange and pressuremedium communicating with both said pressure chambers for applyingequalized pressure on said liquid medium and female form forcompressingsaid material and causing rapid heat exchange therewiththrough the thin metal of thefemale form, and an apertured breatherplate. interposed between said blanket and the periphery of said femaleform to permit entrapped gas to escape therethrough.

3. Apparatus for forming material involving the application of pressureand heat exchange, including a female contour form of thin metal forrapidheat transmission, a cradle within which said form is supported andsealed to enclose a pressure chamber, a complementary male formextending into said female form with said material therebetween, saidmale form comprising a plug of compressible resilient material, aflexible and resilient blanket associated with said plug, a chambercover sealed over said blanket to provide a pressure chambertherebetween, means for securing said chamber cover over said cradlewith said forms in material engaging relation, a source of'liquidpressure medium communicat- When the assembly is placed in the cyl nder'ing with the last mentioned pressure chamber to including a femalecontour form of thin metal for rapid heat transmission, a complementarymale form extending into said female form with said materialtherebetween, said male form comprising a plug of compressible resilientmaterial, a flexible and resilient blanket associated with said plug,clamping means for sealing said plug between said blanket and femaleform, a closed pressure tank for supporting said forms therein andproviding a surrounding pressure chamber, means for introducing a heatexchange and pressure medium into said pressure tank for exertingequalized pressure on said forms to compress the material therebetween,and a liquid containing ring surrounding said blanket for providing abath of protective liquid thereover to prevent direct contact therewithof the said pressure medium.

WILLIAM B. AHERN.

